The title was the second of the year for the 21-year-old Kirilenko, who was seeded No. 2 in the tournament.
Sanchez, who was unseeded, played in her first final on the women's tour.
"It's my second title this year and I'm really happy everything is working so well on clay, because last year I didn't do so well during this season," Kirilenko said.
"Today I concentrated really well and kept any negative emotions inside. I played consistently and saw everything quite clearly. I feel great."